Well strings such as drill strings, production strings, drive strings, etc. are used in borehole operations. During such operations, it may be useful or necessary to centralize the well string to prevent it from wearing against or sticking to the borehole wall, to ensure an annular space is maintained between the wells string and the borehole wall, etc. Centralizers, which are sometimes alternately termed stabilizers, have been used to effect such centralization. Centralizers generally each include an axial bore and an outer surface and are installed to encircle the wellstring with a portion of the well string extending through the bore of the centralizer.
Plastic centralizers are known. Some plastic centralizers have suffered from damage at their ends where the centralizer is acted on by the formation and the casing about which it is installed. To address the end-wise damage of the centralizers, metal rings have been installed as by securing to or imbedding in the ends of some centralizers. Metal rings are intended to provide reinforcement, stabilization and enhanced durability at the ends of the centralizer, where it often undergoes greater stresses as by abutment against borehole ledges, other string components such as collars, shoulders, rings, etc. However, such rings have in some cases become detached from the plastic part of the centralizer or the plastic material of the centralizer has deformed to ride up over the ring.